Method and apparatus for forming sift proof glued flap seals for cartons

ABSTRACT

An adhesive applicator is described which includes five adhesive applying nozzles for placing beads of fluid adhesive on a line of moving cartons. Four of the nozzles are moved diagonally with respect to the path along which cartons are moved beneath the adhesive applicator. One nozzle is stationary and is used to produce a straight line of adhesive paralleling the path of motion. The moving nozzles are mounted just above the flaps of the carton which are held in a horizontal position. Each moving nozzle is mounted on a pivot axis positioned above the nozzle opening and oriented at an angle of approximately 30* to the direction of carton motion so that relative movement between the carton and nozzle is at right angles to the main axis of the carton producing a bead across the flaps which is positioned perpendicular to the direction of carton travel. In this manner, an adhesive bead of considerable thickness and of just the desired pattern is applied to the flaps while the cartons move continuously below the glue nozzles. When the flaps are folded inwardly one after the other, the pressure on the adhesive beads causes a squeezing out of adhesive into all the voids of the flap contact area thereby producing a sift proof seal.

United States Patent [191 Rejsa [451 Aug. 27, 1974 METHOD AND APPARATUS FOR FORMING SIFI PROOF GLUED FLAP SEALS FOR CARTONS [75] Inventor: Jack J. Rejsa, Minneapolis, Minn.

[52] US. Cl 53/47, 53/383, 118/323 [51] Int. Cl B65b 7/20 [58] Field of Search 53/47, 383; 118/323 [56] References Cited UNITED STATES PATENTS 10/1933 Merritt et al. [18/323 10/1934 Bergstein 53/47 Primary Examiner-Travis S. McGehee Attorney, Agent, or Firm.lames V. Harmon; Michael D. Ellwein; Ronald E. Lund [57] ABSTRACT An adhesive applicator is described which includes five adhesive applying nozzles for placing beads of fluid adhesive on a line of moving cartons. Four of the nozzles are moved diagonally with respect to the path along which cartons are moved beneath the adhesive applicator. One nozzle is stationary and is used to produce a straight line of adhesive paralleling the path of motion. The moving nozzles are mounted just above the flaps of the carton which are held in a horizontal position. Each moving nozzle is mounted on a pivot axis positioned above the nozzle opening and oriented at an angle of approximately 30 to the direction of carton motion so that relative movement between the carton and nozzle is at right angles to the main axis of the carton producing a bead across the flaps which is positioned perpendicular to the direction of carton travel. In this manner, an adhesive bead of considerable thickness and of just the desired pattern is applied to the flaps while the cartons move continuously below the glue nozzles. When the flaps are folded inwardly one after the other, the pressure on the adhesive beads causes a squeezing out of adhesive into all the voids of the flap contact area thereby producing a sift proof seal.

6 Claims, 6 Drawing Figures Znd OELASZ'FOLD PATENTEUMIBZHSH Z06 oeusrrow METHOD AND APPARATUS FOR FORMING SIFI PROOF GLUED FLAP SEALS FOR CARTONS FIELD OF THE INVENTION The present invention relates to carton gluing and more particularly to glue applicators for applying beads of glue to cartons and to a method of sift proofing cartons.

THE PRIOR ART Although unlined paperbound cartons have been used for years to ship flour, dry mixes and other powders, no satisfactory sift-proof seal has been successfully developed. Thus, unsightly accumulation of powder on the cartons is common. The powder can also attract insect pests and make directions difficult to read.

Conventional methods of adhesive application such as wheels, spray application, wipers, etc. apply the adhesive in a very thin layer with little squeeze-out and also apply adhesive to areas where it is not effective. Moreover, existing jet applicators do not apply adhesive beads at an angle of 90 to the direction of carton travel and have not as far as is known been successful in producing a sift-proof carton.

Moreover, prior adhesive applicators of the type described have been slow in operation, were not adapted to applying adhesive in bead form to a line of continuously moving cartons, were ineffective in producing sift-proof cartons or have been subject to malfunction particularly with respect to precise timing of the start and stop of the adhesive application. Other applicators of the general type described have not been capable of operating at the speeds for which the present invention is designed, namely, on the order of about 200 to 300 cartons per minute.

OBJECTS or THE INVENTION The primary objects are to provide a) a method of applying adhesive more effective than adhesive wheels, spray applicators, wipers, etc. for producing a reliable sift-proof seal for a carton of the type with flaps which are folded in overlapped position and glued in place, b) provision for utilizing the flow characteristics of adhesives for effectively forcing adhesive into all of the interstices between the layers of the folded carton end flaps to thereby reliably seal the carton flaps against the leakage of powdered contents, c) provision for reliably applying adhesive as a bead at an angle of 90 to the direction of carton travel without stopping the motion of a line of moving cartons, d) provision for reliably starting and stopping the flow of adhesive and for controlling the location of the bead on the carton, e) and more specifically provision for applying adhesive as a head which extends both longitudinally and transversely and for utilizing the fluidity of the adhesive to allow excess adhesive to be squeezed into the interstices between carton flaps to thereby reliably form a carton resistant to sifting of powdered contents.

THE FIGURES FIG. 1 is a plan view of the apparatus.

FIG. 2 is a vertical sectional view taken on line 2-2 of FIG. 1.

FIG. 3 is a vertical sectional view taken on line 33 of FIG. 1.

SUMMARY OF THE INVENTION Briefly, the present invention provides a method of forming sift-proof cartons which comprises providing a carton with end flaps and placing a first pair of the opposing flaps in a predetermined position adapted to receive adhesive on their exposed surfaces. The second opposed flaps are preferably folded centrally toward I one another and adhesive is applied to the first pair of flaps at right angles to the fold line of each of the first pair of flaps. Preferably adhesive is also applied along a line running parallel to the fold line of one of the flaps. The bead of adhesive has a height which is on the same order as the width thereof and the flaps are folded to the closed position while the adhesive is in a fluid condition.

The invention also embodies an apparatus for applying adhesive, simultaneously advancing the cartons along a predetermined axis and includes at least one moving nozzle which deposits the adhesive along the line extending transverse to the direction of packaged movement. A stationary nozzle is employed for depositing adhesive along a line parallel to the axis of package motion.

DESCRIPTION OF THE PREFERRED EMBODIMENT Refer first to FIG. 5 which illustrates a portion of the top of a carton prior to folding the flaps to the closed position. The carton indicated generally at 10 is provided with vertically disposed carton panels 12 including an end panel 12a and side panels 12b of a substantially larger size. The top flaps include a left top flap 12c, a center top flap 12d, a right side top flap l2e, and a rear top flap 12f. Laterally extending beads of adhesive 16 and 18 are applied as described below in a direction extending normal to the longitudinal axis of the carton as seen from above, i.e., along the axes of flaps 12c and l2e while a longitudinally extending bead 14 is applied to flap l2e in approximately the center. It should be noted that the beads 16 and 18 extend across the gap between the flaps 12d, 12f and the flaps on either side thereof. The transverse beads are located approximately V8 to V2 inch and preferably about /4'IIICI'I from theend panels of the carton on either end. At the time of the folding operation, the beads 16, 18 and 14 are still in a wet or plastic condition, i.e., fluid so that they are capable of flowing whereupon when flap is folded downwardly over flaps 12d and 12f and the flap l2e is placed on top of flap 12c. When this is done the fluid adhesive will flow toward the end panels 12a as well as toward the center of the container and a portion of it will be forced into the cracks along the side edges of flap 12d and 12f thereby reliably sealing the comers and edges to provide a substantially sift-proof container.

The adhesive applicator will now be described with reference to FIGS. 14. The adhesive applicator includes a plurality of nozzles to apply the several beads 16, 18 and 14 to the carton as the carton moves continuously. The nozzle which applies the bead 14 is stationary while the remaining nozzles of which there are four oscillate with the center of oscillation of the nozzle shaft at an oblique angle to the direction of travel of the carton so that the bead of adhesive may be applied to the carton flap at an angle of 90 with respect to the direction of carton travel. To impart oscillatory movement to the nozzles it is convenient to suspend each moving nozzle from a pivot point positioned above the cartons and to provide a means for swinging the nozzle back and forth below.

The primary advantage of this manner of applying adhesive is that when the flaps are folded to the closed position, the adhesive beads are pressed together in bead to bead relationship resulting in a squeezing out of adhesive into all of the voids and interstices of the flap contact area. This is particularly important because the adhesive is pressed into the carton corners where the most leaks occur while in prior methods of adhesive application, (wheels, wipers. sprays, etc.) the adhesive is applied in thin layers with little squeeze-out. These prior systems, moreover, apply adhesive to areas where it is not effective. The adhesive can comprise a hotmelt adhesive, a cold resin type adhesive with a water base or the like provided only that the adhesive is thick enough to form a bead. The adhesive nozzle moving means is preferably connected directly to the carton advancing mechanism and the nozzle can be turned on and off by actuation through suitable photoelectric cell or other sensor operatively connected to the nozzle and adapted to operate when each carton is moved to a predetermined point on the machine.

Concerning the details of the nozzle construction refer now to FIGS. 1-4. As seen best in FIG. 1, the cartons enter the apparatus from the right hand side and travel toward the left with the flaps 12c and 12e folded outwardly while the flaps 12d and 12f are folded centrally. The flaps are held in the selected position by the usual flap positioning rods 25. Motion is imparted to the cartons by a belt conveyor 27 driven by a motor driving sprockets 29 and 31.

The controls for turning on and off the nozzles, starting and stopping the flow through the nozzles will now be described with particular reference to FIG. 4. Alternating current is provided through a commercial power line consisting of conductors 89 and 90 connected to a DC power supply 102 which serves to prevent irregularities in operation due to fluctuation in line voltage and thereby provides more uniform operation. DC power from supply 102 is supplied to photoelectric control units 100 and 101 which open and close moving nozzles 122 to 128a and stationary nozzle 130a respectively. Adhesive is supplied through a line 142 from a supply container 140. The photoelectric control unit 100 is wired to solenoid operated valves 104 and 106 by conductor 100a which is coupled through the DC power supply by a normally open switch 100s. Similarly, photoelectric control unit 101 is connected by a conductor 101 a to the operated valves 108 and 110 which receive DC power from supply 102 when the normally open switch 1015 is closed. A pheumatic supply compressor 111 provides pressure to the solenoid operated shut-off valves. The valve 104 is connected via line 121 to open all of the adhesive flow control actuators 122, 124, 126 and 128 which are coupled to the moving nozzles 122a, 124a, 126a and 1280 respectively. The solenoid operated valve 106 is coupled via line 123 to valves 122-128 for closing the same to thereby shut off the flow of adhesive supply. The valve 108 is connected via line 132 to valve 130, the stationary, the pneumatically operated valve 130 of nozzle 130a and the valve is connected via pipe 134 to close valve of the stationary nozzle 130a. Thus, because the opening and closing of the nozzles is done by separate valves, much faster time response is provided than if the same valve were used since the lines are filled at all times with hydraulic fluid and there is no requirement for the pressure to build up within the valves. On the otherhand, if the same valves were used for emptying and filling, some of the lines would be empty and a time lag would occur while hydraulic pressure was built up within the empty lines.

Photocell 136 and 138 positioned in substantial alignment with the nozzles 122a and 130a respectively and in a location to be actuated and in this way sensing the leading edge of the flaps 12c. The photocell 136 is connected to the photoelectric control unit 100 by wires 136a and photocell 138 is connected to photoelectric control unit 101 by conductors 1380 so that during operation as the leading edge of the flap 12c breaks, the beam of photocell 136 the normally open switch 100s closes thereby opening all four of the nozzles 122a to 1280 the long axis and axis of motion of the carton as seen from above is designated A in FIG. 5. The beads of adhesive 16 and 18 are there laid down at right angles to fold lines of flaps 12c and 12e. When the conductors 138a are energized, the noramlly open switch 101s closes thereby opening the stationary nozzle 130a. When conductors 136a are de-energized after an adjustable time delay, valve 106 closes all four nozzles.

Refer now to FIGS. 1, 2, and 3 with reference to the construction of the nozzles themselves. As seen in the figures, the hydralically operated adhesive valves 122, 124, 126, and 128 are mounted in a fixed position and supported in any convenient manner upon a framework F, only a portion of which is shown. While four of the moving nozzles are provided, only one will be described in detail since they are identical to one another except for their locations.

As shown in FIG. 2, a rotary coupling is provided between the valve 124 and the nozzle 124a. Coupling 150 has an internal bearing 150a which enables the nozzle 124a to pivot about the axis 151 of the adhesive duct 153 within the outlet portion 150b of the coupling 150. From duct 153 the adhesive enters a block 150c and through the nozzle 1240.

As seen in FIG. 1, the motor M is also coupled to a positive drive element such as a timing belt or chain to a right angle gear box 162 having an outlet shaft to which is secured a timing cam 164 that engages a follower 166, suspended from an arm 167 pivoted at upon the supporting framework F and connected via an adjustable push rod 168 to a nozzle operating shaft 169 which is secured to the pivoted nozzles 122a and 128a which are connected to the lower ends of the nozzle blocks 150c of the nozzles 122a and 128a. Coupling links 170 and 172 respectively connect the shaft 169 to the nozzle blocks 1506 of the nozzles 124, and 126 respectively thereby linking the push rod 168 and follower 166 to all of the pivoted noule blocks upon which the nozzles 122a-128a are mounted. A spring 178 is connected between the top of the arm 167 on the framework F to maintain the follower 166 in contact with cam 164. r

As shown in FIG. 1, the axes of all of the rotary couplings 150, the links 168-172 and the cam 164 are oriented at an oblique angle with respect to the axis of movement of the cartons. The angle between the axis of rotation of the nozzles is determined by the carton determinations and glue pattern determinations. Thus, as seen in FIG. 5, by joining a line between the beginning of bead 16 at the upper left and the beginning of bead 18 at the lower right an angle is designed with the axis A of motion and it is this angle to which the rotary joints of the glue nozzles are set with respect to the path A. Thus, during operation as the cam 164 rotates the follower 166 and the links cause the nozzles to oscillate so that their tips follow a line which is oriented at an angle to the path taken by the cartons beneath the nozzles and because the conveyor belt 27 and the timing belt 160 are synchronized with the rotation of the cam 164, the forward motion of the carton is accompanied by transverse movement of the tips of each of the nozzles relative to the carton. It is in this way that the adhesive is reliably applied in a bead at a right angle to the direction of travel of the carton.

The cartons thus move continuously beneath the adhesive applicator as a bead of adhesive is applied at right angles to the direction of carton motion and since different valves are employed for starting and stopping the adhesive flow, the initiation and shut-off of the adhesive can be accomplished in a relatively short period of time, for example, the adhesive flow can be reliably started and stopped in 25 milliseconds, and will produce a bead of adhesive 1 /2 inches long with the cartons traveling at a speed of about 160 FT/min. Additionally, because DC power is used to operate the variations in on time or off time will not vary as a result of the fluctuations in AC current.

It should be noted that the adhesive is applied in a bead form. By the term bead it is meant having a substantial height, the average height of the bead being on the same order as its width (from /2 to 1 /2 times the width) to provide for the possibility of squeeze-out when the adhesive beads are pressed together bead to bead and it is a result of the squeeze-out or flow of the bead and the contact of the beads with one another which causes the adhesive to flow into all of the voids of the flap contact area which is so important in filling the interstices between the edges and corners of the carton flaps to prevent sifting of powdered contents from the container. l have found that when a liquid adhesive such as a water base resin emulsion glue, a bead of about l/l6 inch diameter can be used. A bead of about the same size is satisfactory when a hot melt adhesive is used. After the adhesive has been applied, the flaps are folded to the closed position conventionally, for example, by engagement with folding shoes (not shown). As can be seen best in FIG. 6, the adhesive beads 14, 16 and 18 are spread as indicated at 20 both transversely and longitudinally of the package when the carton flaps are folded to the closed position. The adhesive will flow into the cracks between the superimposed flaps and between the flaps and the comer openings in the carton thereby sealing the package against sifting.

I claim:

1. A method of providing a sift proof carton comprising; providing a carton having four end flaps on one end thereof, placing a first pair of opposing flaps in an outwardly spread position and the other two opposing flaps in an inwardly folded position adapted to receive adhesive on their exposed surfaces, advancing the carton on an axis parallel to the edges of the flaps, applying adhesive to the exposed surfaces in the form of beads at each end of each of the first pair of flaps having a cross-sectional height which is on the same order as the width thereof along two lines extending at right angles to the axis of motion of the carton, applying another bead of adhesive to one of the first pair of flaps along a line running parallel to the fold lines of the first pair and extending from the bead of adhesive at one end to the bead of adhesive at the other end, folding the first pair of flaps onto the other flaps to thereby press the beads of adhesive onto themselves and spread the adhesive between the flaps to thereby force at least part of the adhesive into the interstices between the folds of the flaps to provide a carton resistant to the sifting of powdered contents therein.

2. An apparatus for dispensing adhesive for sealing a carton to provide a sift proof seal therein comprising in combination conveyor means for advancing the cartons in an upright position, means for holding the side flaps in a horizontally disposed laterally extending position and the end flaps in a horizontal position extending centrally from the edges of the top of the carton, movable nozzle means for expelling adhesive onto the flaps, valve means for the nozzle, said nozzles being adapted to move along an axis positioned obliquely to the axis of movement of the cartons, m eans for sensing the position of said cartons in succession and operatively connected to the valve means, the valve means being connected to the nozzles for starting and stopping the flow of adhesive therethrough, stationary nozzle means positioned to apply a bead of adhesive along the length of one of the side flaps whereby actuation of the sensing means controls the flow of adhesive from the moving nozzles onto the exposed surfaces of the flaps to form a bead located adjacent to both the leading and the trailing end of the carton.

3. The apparatus according to claim 2 wherein the nozzles are mounted for pivotal movement along axes extending at an oblique angle with respect to the axis of carton movement and the side edges of the carton flaps, each nozzle includes a nozzle opening positioned in spaced relationship from its axis of pivotal movement, linkage means connected to the nozzles and actuating means operatively connected to the linkage for oscillating the free ends of the nozzles and means foroperating the actuating means in timed relationship with the conveyor for advancing the cartons.

4. The apparatus of claim 3 wherein the actuating means comprises a rotating cam in operative engagement with said link means and means to force the link means against the cam.

5. The apparatus of claim 2 wherein five nozzles are provided, one being stationary and the other four comprising moving nozzles positioned for pivotal movement on parallel axes oriented obliquely with respect to the hinge connection between the side flaps and the carton, the moving nozzles comprising a first pair positioned to deposit adhesive adjacent the leading edges of the side flaps and a second pair positioned to deposit adhesive adjacent to the trailing edges of the same flaps, the nozzle openings being positioned between the pivot axes and the flaps, means for simultaneously oscillating the nozzles in the same direction, means operatively associated between the nozzle oscillating means ing from one end to the other of one side flap on an axis parallel to the fold line of the side flap.

6. The apparatus of claim 5 wherein the adhesive applied from the moving nozzles is deposited in a ribbon extending substantially from the free marginal edge of the side flaps centrally of the carton and onto the outside surface of the adjacent end flaps and in overlapping relationship with the interstice between the side flaps and the end flaps. 

1. A method of providing a sift proof carton comprising; providing a carton having four end flaps on one end thereof, placing a first pair of opposing flaps in an outwardly spread position and the other two opposing flaps in an inwardly folded position adapted to receive adhesive on their exposed surfaces, advancing the carton on an axis parallel to the edges of the flaps, applying adhesive to the exposed surfaces in the form of beads at each end of each of the first pair of flaps having a cross-sectional height which is on the same order as the width thereof along two lines extending at right angles to the axis of motion of the carton, applying another bead of adhesive to one of the first pair of flaps along a line running parallel to the fold lines of the first pair and extending from the bead of adhesive at one end to the bead of adhesive at the other end, folding the first pair of flaps onto the other flaps to thereby press the beads of adhesive onto themselves and spread the adhesive between the flaps to thereby force at least part of the adhesive into the interstices between the folds of the flaps to provide a carton resistant to the sifting of powdered contents therein.
 2. An apparatus for dispensing adhesive for sealing a carton to provide a sift proof seal therein comprising in combination conveyor means for advancing the cartons in an upright position, means for holding the side flaps in a horizontally disposed laterally extending position and the end flaps in a horizontal position extending centrally from the edges of the top of the carton, movable nozzle means for expelling adhesive onto the flaps, valve means for the nozzle, said nozzles being adapted to move along an axis positioned obliquely to the axis of movement of the cartons, m eans for sensing the position of said cartons in succession and operatively connected to the valve means, the valve means being connected to the nozzles for starting and stopping the flow of adhesive therethrough, stationary nozzle means positioned to apply a bead of adhesive along the length of one of the side flaps whereby actuation of the sensing means controls the flow of adhesive from the moving nozzles onto the exposed surfaces of the flaps to form a bead located adjacent to both the leading and the trailing end of the carton.
 3. The apparatus according to claim 2 wherein the nozzles are mounted for pivotal movement along axes extending at an oblique angle with respect to the axis of carton movement and the side edges of the carton flaps, each nozzle includes a nozzle opening positioned in spaced relationship from its axis of pivotal movement, linkage means connected to the nozzles and actuating means operatively connected to the linkage for oscillating the free ends of the nozzles and means for operating the actuating means in timed relationship with the conveyor for advancing the cartons.
 4. The apparatus of claim 3 wherein the actuating means comprises a rotating cam in operative engagement with said link means and means to force the link means against the cam.
 5. The apparatus of claim 2 wherein five nozzles are provided, one being stationary and the other four comprising moving nozzles positioned for pivotal movement on parallel axes oriented obliquely with respect to the hinge connection between the side flaps and the carton, the moving nozzles comprising a first pair positioned to deposit adhesive adjacent the leading edges of the side flaps and a second pair positioned to deposit adhesive adjacent to the trailing edges of the same flaps, the nozzle openings being positioned between the pivot axes and the flaps, means for simultaneously oscillating the nozzles in the same direction, means operatively associated between the nozzle oscillating means and the conveyor for synchronizing the conveyor and the nozzle oscillating means, means communicating with the nozzles for supplying adhesive to the nozzles, said valve means starting and interrupting the flow of adhesive through the nozzles in timed relationship with movement of the nozzles in a selected direction while the nozzles are positioned adjacent the ends of the flaps, and a means for starting and interrupting the flow of adhesive through the stationary nozzle when the corresponding flap passes into proximity with the stationary nozzle to thereby deposit a strip of adhesive extending from one end to the other of one side flap on an axis parallel to the fold line of the side flap.
 6. The apparatus of claim 5 wherein the adhesive applied from the moving nozzles is deposited in a ribbon extending substantially from the free marginal edge of the side flaps centrally of the carton and onto the outside surface of the adjacent end flaps and in overlapping relationship with the interstice between the side flaps and the end flaps. 